Tuesday, March 17, 2009

Flow Injection Analysis

Flow injection analysis ( FIA ) is an analytical technique that we use to measure the concentration of micro and trace elements in seawater. It yields metal concentrations that compare very well with traditional atomic absorption spectrophotometry (AAS). Its main advantage is that it can be used shipboard to gather near real time information on natural metal distributions or in ecosystem manipulations such as the IronEx experiment. FIA employs the continuous flow of a reagent stream into which a sample is injected and the resulting color (spectrophotometric) or light (chemiluninescence), or fluorescence is measured.

This technique relies on laminar flow within very small (< 1mm) i.d. tubing to prevent dispersion of the sample slug, and on precise control of reaction time since reactions are frequently not allowed to go to completion. We currently employ FIA for the analysis of Iron (Fe), Copper (Cu), Manganese (Mn), Cobalt (Co), and Zinc, and plan to add Aluminum (Al) to this list very soon.